The present invention relates to can ends, tooling used in a press that is adapted to manufacture the can end and a seaming chuck adapted to hold and rotate a converted can end to be secured to a can body.
Beverage containers and more specifically metallic beverage cans are typically manufactured by affixing a can end to a can body. In some applications, two ends may be affixed on a top side and a bottom side of a can body. More frequently, a can end is affixed to a top end of a can body, which is drawn and wall ironed (xe2x80x9cDWIxe2x80x9d) from a flat sheet of blank material such as aluminum. Due to the potentially high internal pressures generated by carbonated beverages, both the can body and the can end are typically required to sustain internal pressures of 90 psi without catastrophic and permanent deformation. Further, depending on various environmental conditions such as heat, over fill, high carbon dioxide content, and vibration, the internal pressure in a beverage may exceed internal pressures of 90 psi. Recently, can end developments have been focused on engineering various features of the can end including the chuck wall angle in order to reduce the aluminum content in the can end and allow the can end to sustain internal pressures exceeding 90 psi. Examples of these developments can be found in WO 98/34743, WO 02/43895 and WO 02/057148.
As can be seen from the prior art, can end manufacturers have been focusing their attention on engineering various features of the can end including the various angles of the can end chuck wall. Also, can ends must be durable to withstand high internal pressures, and be manufactured with extremely thin materials such as aluminum to decrease the overall cost of the manufacturing process and weight of the finished product. Accordingly, there continuously exists a need for a durable can end, which can withstand the high internal pressures created by carbonated beverages, and the external forces applied during shipping, yet, which is made from durable, lightweight and extremely thin metallic materials. The following patent application describes an improved can end with a unique overall geometry from the prior art that is adapted to be affixed to a standard can body. Additionally, certain configurations of the chuck wall reduce the risk of failure along the chuck wall. The improved can end reduces material usage and will withstand typical internal beverage container pressures. Tooling used to manufacture the improved beverage can end is also described in the patent application.
It has also been found that during the seaming operation of a can end to a can body significant contact of the seaming chuck with the chuck wall can lead to deformation of the chuck wall. In those can ends that have several chuck wall angles, it is important to eliminate deformation of the radii of curvature between the various chuck wall portions to maintain the overall geometry of the can end. Accordingly, there exists a need for a seaming chuck that does not engage the entire chuck wall during the seaming operation of a can end to a can body. The following patent application also describes an improved seaming chuck that engages a portion of the chuck wall and the countersink during a conventional seaming operation of a can end to a standard can body.
It is an object of the invention to provide a can end with a unique geometry.
It is another object of the invention to provide a can end with reduced metal content than the majority of currently available can ends.
It is another object of the invention to provide a can end with certain chuck wall geometries that reduces the risk of catastrophic failure of the can end in the presence of excessive internal pressure within a beverage container.
It is another object of the invention to provide tooling that is adapted to manufacture the can end.
It is another object of the invention to provide a seaming chuck that has a recess that avoids deforming radii of curvature in the chuck wall of the can end.
Certain objects of the invention are obtained by providing a can end that is adapted to be affixed to a can body. The can end has a central panel integrally connected to an inner panel wall, and the connection has a first radius of curvature. A countersink is integrally connected to the inner panel wall, and the countersink has a second radius of curvature. A chuck wall is integrally connected to the countersink, and the chuck wall has three chuck wall sections. A first chuck wall is integrally connected to the countersink, and the first chuck wall has an angle xcex81 of 20 degrees to 35 degrees as measured from an axis perpendicular to the central panel. A second chuck wall is integrally connected to the first chuck wall, the second chuck wall has an angle xcex82 of 4 degrees to 27 degrees as measured from the axis, and the connection has a third radius of curvature. A third chuck wall is integrally connected to the second chuck wall, the third chuck wall has an angle xcex83 of 18 degrees to 32 degrees as measured from the axis, and the connection has a fourth radius of curvature. An end wall is integrally connected to the third chuck wall, the end wall is adapted to be affixed to a flange of a can body, and the can end has a preselected panel depth and a preselected countersink depth. Other objects of the invention are obtained by providing tooling that is adapted to manufacture the can end previously described. Other objects of the invention are obtained by providing a seaming chuck that is adapted to avoid engagement with portions of the chuck wall and the third radius of curvature and the fourth radius of curvature of the can end previously described.